Facsimile machine

ABSTRACT

In a facsimile machine, when a received image data having resolution of standard mode is stored in a reception data memory, the image data is decoded and then converted to image data of two fine or four super fine lines and stored in a first recording data memory. The image data stored in the first recording data memory is subjected to a thin-out processing at a set reduction ratio, then stored in a second recording data memory and finally recorded on a recording sheet.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a facsimile machine, and particularly to afacsimile machine capable of conducting a reduction processing ofreceived image data or image data read out to conduct a copyingoperation.

2. Description of Related Art

In general, facsimile machines have been widely used, and their wide usehas led to the facsimile machines having high functions. For example,the facsimile machine has not only a function of transmitting andreceiving image data of an original in a standard mode which correspondsto a low resolution, but also a function of transmitting image data in afine or super fine mode which correspond to higher resolution. Further,facsimile machines which are provided with a copying function and areducing function have been practically used.

In this kind of facsimile machine, when received image data whoseresolution corresponds to any one of the standard mode, the fine mode orthe super fine mode are reduced, for example, using a reduction ratio of80% to record reduced image data on a recording sheet, the receivedimage data are stored in a reception memory, and a number of line dataconstituting the image data are first subjected to a thin-out processingfor thinning out the image data of one line in an auxiliary scanningdirection. The reduced image data which has been subjected to thethin-out processing are also subjected to a thin-out processing forthinning out dot data in a main scanning direction. The reduced imagedata which have been subjected to the thin-out processing in theauxiliary and main scanning directions as described above are preparedas recording data at the designated resolution and the recording dataare recorded on the recording sheet.

As described above, in the conventional facsimile machine which isprovided with the copying function and the reducing function and cantransmit and receive image data of an original at a plurality ofresolutions, for a recording operation under data reduction, a number ofreceived one-line image data are subjected to thin-out processing inaccordance with a reduction ratio in the auxiliary and main scanningdirections line by line to finally prepare recording data and record iton a recording sheet. Particularly for a reducing operation ofstandard-pitch image data which corresponds to a low resolution, theweight of the one-line image data to the whole image data is increasedand, thus, the plural one-line image data are required to be thinned outin the auxiliary scanning direction in accordance with the reductionratio. Therefore, there is a problem that image quality of the recordedimage is deteriorated and moire occurs.

SUMMARY OF THE INVENTION

An object of the invention is to provide a facsimile machine in whichreduced image data is prepared on the basis of received image data orimage data read out for a copying operation with improving image qualityof the recorded image.

In order to attain the above object, the facsimile machine according tothe invention includes reception means for receiving image datatransmitted from an external source, read-out means for reading anoriginal, storage means for storing image data supplied from thereception means or the read-out means and record means for recordingimage data on a recording sheet at an indicated resolution, furthercomprises a reduction ratio setting means for setting a reduction ratioat which the image data stored in the recording means is recorded on therecording sheet, and reduced image data preparing means for convertingthe image data read out from the storage means to high-density imagedata which has a higher resolution in the auxiliary scanning directionthan an indicated resolution and conducting a thin-out processing in theauxiliary scanning direction on the high-density image data on the basisof the reduction ratio set by the reduction ratio setting means toprepare reduced image data.

In the facsimile machine thus structured, the image data which isreceived by the reception means or supplied from the read-out means arestored in the storage means. The reduced image data preparing meansreads out the image data from the storage means to convert it tohigh-density image data which has a higher resolution in the auxiliaryscanning direction than the indicated resolution, that is, to image datawhose line data number is larger than that of the received image data,and conducts this high-density image data to the thin-out processing inthe auxiliary scanning direction on the basis of the reduction ratio setby the reduction ratio setting means to thereby prepare the reducedimage data. Thereafter, the reduced image data thus prepared aresubjected to the thin-out processing in the main scanning direction, andthen the recording image data reduced in the auxiliary and main scanningdirections are finally recorded on the recording sheet.

As described above, the image data read out from the storage means areconverted to the high-density image data which has higher resolution inthe auxiliary scanning direction than the indicated resolution, that is,to the image data whose line data number is larger than that of thereceived image data, and then subjected to the thin-out processing basedon the reduction ratio in the auxiliary scanning direction. Therefore,the line data number to be thinned out becomes larger, the weight (rate)of the one-line image data to the whole image data is reduced, and thethinned-out one-line data are dispersed in the auxiliary scanningdirection so that the reduced image data can be prepared to improve theimage quality of the recorded image.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, in which:

FIG. 1 is a perspective view of a facsimile machine according to anembodiment of the invention;

FIG. 2 is a longitudinal-sectional view of a main part of the innerstructure of the facsimile machine;

FIG. 3 is a block diagram showing a control system for the facsimilemachine;

FIG. 4 is a flowchart showing a routine for a reduced image datapreparation control;

FIG. 5 is a schematic view of image data stored in a decoding datamemory;

FIG. 6 is a schematic view of high-density image data stored in a firstrecording data memory; and

FIG. 7 is a schematic view of reduced image data which has beensubjected to thin-out processing in the auxiliary scanning direction andstored in a second recording data memory.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiment relates to a case where the invention is applied to afacsimile machine which is capable of recording received image data ofan original on a recording sheet and has a copying function.

The structure of the facsimile machine will be briefly described withreference to FIGS. 1 and 2.

As shown in FIG. 1, an operation panel 3 is provided at the front sideof the upper portion of a main frame 2 of the facsimile machine 1. Theoperation panel 3 is provided with a plurality of function keys, forexecuting transmission processing of original data and of copyingprocessing, such as a transmission key, a copying key, a reduction ratiosetting key, and ten keys. Further, an original mount portion 4 isprovided just behind the operation panel 3. On the original mountportion 4 can be mounted plural originals G which comprise plural kindsof cut sheets, such as A-4 size sheets and B-5 size sheets.

Next, a read-out device 5 for reading out an original G set on theoriginal mount portion 4 will be described with reference to FIG. 2.

A first sheet passage 7 for guiding an original G, set on the originalmount portion 4, through the main frame is formed by plural guide walls6 inside of the main frame 2 and just below the operation panel 3. Apair of sheet supply rollers 8 for supplying the original G is disposedat the middle portion of the first sheet passage 7. Further, a pair ofsheet discharge rollers 9 for discharging the original G out of the mainframe are disposed at the end portion of the downstream side of thefirst sheet passage 7. These sheet supply rollers 8 and the sheetdischarge rollers 9 are rotationally driven in a sheet feeding directionin synchronism with an original feeding motor 35 (see FIG. 3).

A read-out sensor 10 for reading the original G fed by the sheet supplyrollers 8 and a light-emitting diode (LED) 11, serving as a light sourcefor the reading (see FIG. 3), are disposed just at the upstream side ofthe sheet supply rollers 8 to confront the first sheet passage 7. Theread-out sensor 10 comprises a CCD line image sensor and is so designedas to store charges through reflected light from the light-emittingdiode 11 to read image data of one line of the original G.

Next, a recording device 21, provided inside of the main frame 2 andserving to store on a recording sheet P image data of an original Greceived from the external source or read by the read-out device 5 forcopying, and a sheet feed device 15 for feeding the recording sheet Pwill be described with reference to FIG. 2.

A sheet cassette 16 for stocking a plurality of recording sheets P,formed of cut sheets such as A-4 size sheets, B-5 sheets or the like, isdetachably mounted at the lower end portion of the inside of the mainframe 2. A second guide passage 18 is formed by a plurality of guidewalls 17 so as to extend from the rear end portion of the sheet cassette16 in U-shaped form. A sheet supply roller 19 is disposed at thestarting portion of the second guide passage 18 and a plurality of sheetfeed rollers 20 and a thermal head 22, comprising a large number of (forexample 1728) heating elements which are arranged on a row at apredetermined length, are provided midway in the second guide passage 18so as to confront the second guide passage 18. In the embodiment thelength of the row on which the heating elements are arranged is the sameas that of the largest recording sheet in the direction perpendicular tothe recording sheet feeding direction. The sheet supply roller 19 andthe sheet feed rollers 20 are rotationally driven in synchronism withthe recording sheet feeding motor 37 (see FIG. 3).

In addition, a ribbon cassette 23, for accommodating an ink ribbon 24whose width corresponds to the width of the thermal head 22, is providedat the upper side of the second guide passage 18. The ink ribbon 24 iswound around a ribbon supply spool 22a which is rotatably supported onthe ribbon cassette 23, passed by the thermal head 22 and taken up by aribbon take-out spool 22b.

Upon the start of the recording operation, an uppermost recording sheetP of the sheets P stocked in the sheet cassette 16 is supplied to thesecond guide passage 18 by the sheet supply roller 19. The recordingsheet P is subjected to a recording operation with ink of the ink ribbon24 through a heating operation of the thermal head 22 while being fedalong the second guide passage 18 at a predetermined speed. Thereafter,the recording sheet P, thus recorded, is discharged through the secondguide passage 18 to the outside of the main frame. The thermal head 22and the ribbon cassette 23 constitute the recording device 21.

Next, the control system for the facsimile machine will be describedwith reference to the block diagram of FIG. 3.

A communication control device 25 is connected to an input/outputinterface 38 of a control device C and to a communication modem 26 and anet control unit (NCU) 27. The communication control device 25 executesfacsimile control when control signals or image data received from theinput/output interface 38 are transmitted to the communication modem 26or when control signals or image data received from the communicationmodem 26 are transmitted to the input/output interface 38. Thecommunication modem 26 executes modulation control of image data totransmission signals at a transmission time and also executesdemodulation control of received transmission signals to image data at areception time. The net control unit 27 automatically executestransmission control for a transmitter and automatically executesreception control for reception of a transmission from the externalsource.

A driving circuit 30 for driving the thermal head 22 is connected to astrobe signal generating circuit 29 and a P/S (parallel/serial)converter 28. The parallel image data which are output from theinput/output interface 38 are converted to serial image data in the P/Sconverter 28 and supplied to the drive circuit 30. In response to astrobe signal received from the strobe signal generating circuit 29, thedriving circuit 30 outputs a drive signal to the thermal head 22. TheP/S converter 28 is provided with a gate array 31.

Further, the input/output interface 38 of the control device C isconnected to the communication control device 25, a S/P converter 32 forconverting serial image data output from the read-out sensor 10 intoparallel image data, the operation panel 3, a driving circuit 33 for thelight-emitting diode 11, a driving circuit 34 for the original feedingmotor 35, a driving circuit 36 for the recording sheet feeding motor 37,the P/S converter 28 and the strobe signal generating circuit 29.

The control device C comprises a CPU 40, the input/output interface 38connected through a bus 39, such as a data bus, to the CPU 40, a ROM 41and a RAM 50.

The ROM 41 stores a coding control program for preparing transmissionsignals which are obtained by compressing (coding) the image data of theoriginal G at the transmission time, a decoding control program forexpanding (decoding) the coded transmission signals to the image signalat the reception time, a control program for controlling reduced imagedata preparation which is characteristic of this application anddescribed later, and various kinds of control programs for facsimilecommunication control and copying control.

A reception data memory 51 of the RAM 50 is provided with apredetermined memory capacity (for example, 256 Kbytes), and thereceived transmission signals, that is, the coded image data aresuccessively stored. In the decoding data memory 52 are stored the imagedata obtained by decoding the transmission signal received from thereception data memory 51 and the image data read out by the read-outsensor 10 for a copying operation. The first recording data memory 53has stored therein high-density image data of high resolution to whichthe image data of the decoding data memory 52 is converted in a superfine mode. The second recording data memory 54 is stored with reducedimage data which is obtained by thinning out the high-density image dataof the first recording data memory 53 on the basis of the reductionratio. The coding data memory 55 is stored with image data which iscoded at the transmission time. Further, the RAM 50 is provided with awork memory for storing data on a reduction ratio set for the recordingoperation on the recording sheet P, a pointer value, and various kindsof memories for temporarily storing a calculation result of the CPU 4.

In the facsimile machine 1 as described above, all image data which aretransmitted at resolutions corresponding to the super fine mode, thefine mode and the standard mode can be received and recorded. Here,assuming 1/15.4 mm (400 dots/inch) is one super fine line, the superfine mode is defined as a mode for reading out an original G at aresolution corresponding to every one super fine line (400 dots/inch).The fine mode is also defined as a mode for reading out the original Gat a resolution corresponding to every two super fine lines, and thestandard mode is defined as a mode for reading out the original G at aresolution corresponding to every four super fine lines.

Image data which are received at the resolution of the super fine modeare respectively successively recorded on the recording sheet P everytime the recording sheet P is fed by a super fine pitch (about 65 μm).Image data which are received at the resolution of the fine mode arerespectively recorded by an amount of the same two super fine lines, andthese equivalents of two super fine image data are successively recordedevery time the recording sheet P is fed by the super fine pitch for twofeedings. Further, image data which are received at the resolution ofthe standard mode are respectively recorded by an amount of four superfine lines, and these equivalents of the same four super fine image dataare successively recorded every time the recording sheet P is fed by thesuper fine pitch for four feedings.

Next, the routine for reduced image data preparation control, which isexecuted in the control device C of the facsimile machine 1, will bedescribed with reference to a flowchart of FIG. 4. In the description,the following assumption is made. That is, at the start time of thecontrol, the received image data of standard mode resolution are storedin the reception data memory 51 and then decoded, so that the image datacomprising plural line data of a first line data (hereinafter referredto as "A line image data"), a second line data (hereinafter referred toas "B line image data"), a third line data (hereinafter referred to as"C line image data"), a fourth line data (hereinafter referred to as "Dline image data"), a fifth line data (hereinafter referred to as "E lineimage data"), . . . are stored in the decoding data memory 52. Further,with respect to each line data, the data of one byte at the head thereofis represented. The character Si (i=11, 12, 13, . . . ) in the figuresrepresents each step.

Control is started when the image data is stored into the decoding datamemory 52. First, reduction ratio data is read in from the work memoryof the RAM 50 and the reduction ratio (a/b) is used to set variables aand b respectively (S11).

With respect to the image data stored in the decoding data memory 52(see FIG. 5), each line image data is copied to image data of fouridentical super fine lines in the auxiliary scanning direction toprepare high-density image data of high resolution, and then stored inthe first recording data memory 53 (S12). For example, as shown in FIG.6, each of the A line image data, the B line image data, the C lineimage data, the D line image data, the E line image data, . . . iscopied to line image data of four identical super fine lines in theauxiliary scanning direction. That is, the A line image data is copiedto A1 to A4 line image data, the B line image data is copied to B1 to B4line image data, . . . , the E line image data is copied to E1 to E4line image data and so on, respectively, thereby preparing thehigh-density image data of high resolution. The copied high-density datais then stored into the first recording data memory 53.

Subsequently, a variable I, required for the thin-out processing, is setto the variable b of the denominator of the reduction ratio (S13) andthe top addresses in the first and second recording data memories 53 and54 are set to pointers PA and PB respectively at steps S13 and S14 (seeFIGS. 6 and 7). Next, the variable I required for the thin-outprocessing is set to a value obtained by subtracting the numerator a ofthe reduction ratio from the variable I (S15). When the variable I is apositive value (S16:Yes), the pointer value PA is incremented by "1"(S17), and it is judged on the basis of the pointer PA whether any lineimage data exists in the first recording data memory 53 (S18). If thejudgment at the step S18 is "YES", the program returns to the step S15.

On the other hand, if the variable I is a negative value below "0" orequal to "0" (S16: No), the line image data of the first recording datamemory 53 indicated by the pointer PA is stored to the address of thesecond recording data memory 54 which is indicated by the pointer PB(S19). Subsequently, both of the values of pointer PA and the pointer PBare respectively incremented by "1" (S20), and the variable I isincreased by an amount equal to the variable b (S21), thereafter theprogram returns to step S15 through step S18. If no line image data tobe subjected to the reduction processing exists in the first recordingdata memory 53 (S18: No), the control is terminated and the programreturns to the main routine.

That is, if the variable I is a positive value (S16: Yes), the pointerPA is incremented by "1" (S17) and the thin-out processing of the lineimage data is conducted because the line image data of the firstrecording data memory 53 which is skipped due to the increment of thepointer PA is not stored in the second recording data memory 54.

Thereafter, the reduced image data which has been subjected to thethin-out processing in the auxiliary scanning direction in the secondrecording data memory 54 is also subjected to another thin-outprocessing by thinning out the dot data in the main scanning directionin accordance with the reduction ratio by the gate array 31. The reducedimage data which has been finally reduced in the auxiliary scanningdirection and the main scanning direction are supplied through the P/Sconverter 28 to the thermal head 22 and, in response to the drive signalfrom the strobe signal generating circuit 29, the drive circuit 30drives the heating elements to record on the recording sheet P an imagewhich is reduced in accordance with the set reduction ratio.

For example, when the reduction ratio is 80%, the variables a and b areset to "4" and "5", respectively. Accordingly, to obtain thehigh-density image data of the first recording data memory 53 as shownin FIG. 7, "5" is first set to the variable I (S13), and then (5-4)=1 isset to the variable I (S15). Since the variable I is a positive value(S16:Yes), the pointer PA is incremented by "1", and the thin-outprocessing is conducted on "A1 line image data" of the first recordingdata memory 53 as indicated by the pointer PA.

Subsequently, (1-4)=-3 is set to the variable I at step S15, and "A2line image data" indicated by the pointer PA is stored in the secondrecording data memory 54 because the variable I is a negative value.Thereafter, (-3+5)=2 is set to the variable I at step S21, and theprogram returns to step S15. Subsequently, in the same manner asdescribed above, those image data which are located at intervals of fiveline image data away from the head line image data "A1 line image data",that is, "B2 line image data", "C3 line image data", "D4 line imagedata", . . . are successively subjected to the thin-out processing inthe auxiliary scanning direction and, as shown in FIG. 7, the reducedimage data which are reduced at the reduction ratio of 80% in theauxiliary scanning direction are stored in the second recording datamemory 54. Thereafter, each line image data is subjected to the thin-outprocessing of plural dot data in the main scanning direction by the gatearray 31 so as to be reduced at the reduction ratio of 80%. The gatearray 31 removes every fifth dot in the main scanning direction andcloses the dots to eliminate the gaps resulting from removing everyfifth dot. Then the reduced image data which have been finally reducedin the auxiliary and main scanning directions at the reduction ratio of80% are recorded on the recording sheet P by the thermal head 22.

As described above, the image data read from the reception data memory51 are converted to high-density image data of a super fine line unitwhose resolution is higher in the auxiliary scanning direction than theindicated standard mode, that is, whose line data number is four timesas large as that of the received image data, and then subjected to thethin-out processing based on the reduction ratio in the auxiliaryscanning direction. Therefore, the line data number to be subjected tothe thin-out processing is increased, the weight of the one-line imagedata to the whole image data is decreased, and also the one-line imagedata to be thinned out are dispersed in the auxiliary scanning directionso that the reduced image data can be formed with an improvement in theimage quality of the recorded image.

In the above description, the reduction ratio setting means correspondsto the reduction ratio setting keys provided on the operation panel 3and the reduced image data preparing means corresponds to the reducedimage data preparation control as shown in FIG. 4.

At step S12 for the reduced image data preparation control, each linedata of the received image data may be copied to image data of two superfine lines in the auxiliary scanning direction to prepare high-densityimage data of high resolution. The above-described reduced image datapreparation control is applicable to the image data which is received atthe resolution of the fine mode. Further, in the reduced image datapreparation control, when the received data has the resolution of superfine mode, it may be directly subjected to the thin-out processingwithout being converted to the high-density image data of highresolution. Even when the image data read out by the read-out sensor 10is subjected to a reduction copying operation, the reduced image datapreparation control is applicable.

Various modifications may be made to the control of the embodiment onthe basis of existing techniques or obvious techniques by personsskilled in the art without departing from the subject matter of thisinvention. Further, this invention is applicable to various types offacsimile machines having various recording devices such as a thermalsensitive type or a laser type.

As described above, according to the facsimile machine of the invention,the reduction ratio setting means and the reduced image data preparationmeans are provided, and the image data read from the storage means isconverted to the high-density image data of higher resolution in theauxiliary direction than the indicated resolution, that is, the imagedata whose line data number is larger than that of the received imagedata, and then subjected to the thin-out processing based on thereduction ratio in the auxiliary scanning direction. Therefore, thenumber of line data to be thinned-out is increased so that the weight ofthe one-line image data to the whole image data is lowered, and thethinned-out line data are dispersed in the auxiliary scanning directionso that the reduced image data can be prepared with improved the imagequality of the recorded image.

Further, the described capability can be resident in a transmittingfacsimile. For example, when a transmitting facsimile has the ability toprocess large paper sheets, such as 11×17 inches, but the receivingfacsimile can only print on smaller papers, such as 81/2×11 inches, theexchange of protocols will so inform the transmitting facsimile. Basedupon the size sheet which the receiving facsimile can print, thetransmitting facsimile determines a reduction ratio and thins the datato be transmitted on that basis. Thus, the data received has beenreduced prior to transmission and the receiving facsimile prints thedata as received.

What is claimed:
 1. A facsimile machine, comprising:reception means forreceiving image data transmitted from an external source; read-out meansfor reading an original image source as image data; storage means forstoring image data supplied from at least one of said reception meansand said read-out means; record means for recording image data on arecording sheet; reduction ratio setting means for setting a reductionratio; reduced image data preparing means for converting the image dataread out from the storage means to high-density image data which has ahigher resolution in the auxiliary scanning direction than a resolutionwith which the image data is stored in the storage means and forconducting a thin-out processing in the auxiliary scanning direction onthe high-density image data on the basis of the reduction ratio set bythe reduction ratio setting means to prepare reduced image data; andreduced image data output means for outputting the reduced image dataprepared by the reduced image data preparing means to the record meansfor recording the reduced image data, wherein the resolution of thehigh-density image data is the same as the recording image data.
 2. Thefacsimile machine as claimed in claim 1, wherein the reduced image dataoutput means includes a transmitting means for transmitting a reducedimage data to a receiving facsimile machine and the reduction ratiosetting means includes means for setting the reduction ratio based uponprotocols exchanged between the facsimile machine and the receivingfacsimile machine when the transmitting means transmits the reducedimage data.
 3. The facsimile machine is claimed in claim 1, wherein therecord means includes a line recording head extending in the mainscanning direction perpendicular to the auxiliary direction and having arecording length which is same as that of recording sheet in the mainscanning direction.
 4. The facsimile machine as claimed in claim 3,wherein the reduced image data preparing means includes means forconducting a thin-out processing in the main scanning direction on thehigh-density image data on a basis of the reduction ratio.
 5. A methodfor reducing image data in the recording sheet feed direction of afacsimile machine, comprising the steps of:setting a reduction ratio;determining a numerator and a denominator of the reduction ratio;receiving image data; storing the image data in a reception data memory;converting the image data to high-density image data in an auxiliaryscanning direction; storing the high-density image data in a firstrecording data memory; thinning out the high-density image data byreducing the number of lines of the high-density image data based uponthe reduction ratio; and outputting the thinned-out high-density imagedata, wherein a resolution of the high-density image data converted bythe converting step is the same as the output high-density image dataoutputted by the outputting step.
 6. The method as claimed in claim 5,wherein the converting step comprises copying each line of image datainto a space existing between the copied line and an adjacent line. 7.The method as claimed in claim 6, further comprises the step of storingthe thinned-out high-density image data in a second recording datamemory.
 8. The method as claimed in claim 5, wherein the reduction ratiois set by an operator.
 9. The method as claimed in claim 5, wherein thestep of outputting includes transmitting the thinned-out high-densityimage data to a receiving facsimile machine and the reduction ratio isset by the facsimile machine based upon protocols exchanged between thefacsimile machine and the receiving facsimile machine.
 10. The method asclaimed in claim 7, wherein the step of thinning out comprises the stepsof:setting a first pointer to an address for reading a first line imagedata in the first recording data memory; setting a second pointer to anaddress for writing a first line of reduced image data in the secondrecording data memory; setting a control variable equal to thedenominator of the reduction ratio; and executing a thinning out cycleuntil all line image data in the first recording data memory have beenprocessed.
 11. The method as claimed in claim 10, wherein the step ofexecuting the thinning out cycle comprises the steps of:resetting thecontrol variable to a value equal to the control variable minus thenumerator of the reduction ratio; and determining whether the controlvariable is greater than zero.
 12. The method as claimed in claim 11,wherein when the control variable is greater than zero, furthercomprises the steps of:resetting the first pointer to an address forreading a next line image data in the first recording data memory;determining if further line image data exists at the address identifiedby the first pointer in the first recording data memory; and, when it isdetermined that further line image data exists, returning to saidresetting the control variable step.
 13. The method as claimed in claim11, wherein when the control variable is less than or equal to zero,further comprises the steps of:moving the line image data indicated bythe first pointer to an address identified by the second pointer in thesecond recording data memory; resetting the first pointer to an addressfor reading a next line image data in the first recording data memory;resetting the second pointer to an address for writing a next line ofreduced image data in the second recording data memory; reestablishingthe control variable to be equal to the control variable plus thedenominator of the reduction ratio; determining if further line imagedata exists at the address identified by the first pointer in the firstrecording data memory; and, when it is determined that further lineimage data exists, returning to said resetting the control variablestep.
 14. An apparatus for reducing image data in the recording sheetfeed direction of a facsimile machine, comprising:means for setting areduction ratio; means for determining a numerator and a denominator ofthe reduction ratio; means for storing the image data in a receptiondata memory; means for converting the image data to high-density imagedata in an auxiliary scanning direction; means for storing thehigh-density image data in a first recording data memory; means forthinning out the high-density image data by reducing the number of linesof the high-density image data based upon the reduction ratio; and meansfor outputting the thinned-out high-density image data, wherein aresolution of the high-density image data converted by the convertingmeans is the same as the output high-density image data outputted by theoutputting means.
 15. The apparatus as claimed in claim 14, wherein saidmeans for converting comprises means for copying each line of image datainto a space existing between the copied line and an adjacent line. 16.The apparatus as claimed in claim 15, further comprises means forstoring the thinned-out high-density image data in a second recordingdata memory.
 17. The apparatus as claimed in claim 14, wherein saidmeans for setting the reduction ratio is used by an operator.
 18. Theapparatus as claimed in claim 14, wherein said means for outputtingincludes means for transmitting the thinned-out high-density image datato a receiving facsimile machine and said means for setting thereduction ratio sets the reduction ratio based upon protocols exchangedby the facsimile machine and the receiving facsimile machine.
 19. Themethod as claimed in claim 16, wherein the means for thinning outcomprises:means for setting a first pointer to an address for reading afirst line image data in the first recording data memory; means forsetting a second pointer to an address for writing a first line ofreduced image data in the second recording data memory; means forsetting a control variable equal to the denominator of the reductionratio; and means for executing a thinning out cycle until all line imagedata in the first recording data memory have been processed.
 20. Theapparatus as claimed in claim 19, wherein the means for executing thethinning out cycle comprises:means for resetting the control variable toa value equal to the control variable minus the numerator of thereduction ratio; and means for determining whether the control variableis greater than zero.
 21. The apparatus as claimed in claim 20, whereinwhen the control variable is greater than zero, further comprises:meansfor resetting the first pointer to an address for reading a next lineimage data in the first recording data memory; means for determining iffurther line image data exists at the address identified by the firstpointer in the first recording data memory; and, when said means fordetermining determines that further line image data exists; means forreturning to execution of said means for resetting the control variable.22. The apparatus as claimed in claim 20, wherein when the controlvariable is less than or equal to zero, further comprises:means formoving the line image data indicated by the first pointer to an addressidentified by the second pointer in the second recording data memory;means for resetting the first pointer to an address for reading a nextline image data in the first recording data memory; means for resettingthe second pointer to an address for writing a next line of reducedimage data in the second recording data memory; means for reestablishingthe control variable to be equal to the control variable plus thedenominator of the reduction ratio; means for determining if furtherline image data exists at the address identified by the first pointer inthe first recording data memory; and, when said means for determiningdetermines that further line image data exists, means for returning toexecution of said means for resetting the control variable.